Undergrad Twin Paradox Resolution

  • Thread starter Thread starter CSnowden
  • Start date Start date
  • Tags Tags
    Special relativity
Click For Summary
The discussion addresses the logical flaws in the common explanations of the Twins Paradox, particularly regarding length contraction and time dilation. It highlights that each twin perceives the other's clock differently due to their relative motion, with the rocket twin experiencing time passing more slowly on Earth. The misconception that both twins' experiences are symmetrical is identified as a key issue, as the rocket twin's journey involves acceleration and deceleration, breaking the symmetry. The conversation suggests that while length contraction can be used to explain the paradox, it may confuse those already struggling with time dilation concepts. Ultimately, clarifying these misconceptions is essential for understanding the resolution of the Twins Paradox.
CSnowden
Messages
27
Reaction score
4
TL;DR
Looking for logical fault in a simple explanation of the Twins Paradox
In what sense is the following explanation of the Twins Paradox faulty in logic:

Each twin views the other as length contracted, but the twin on earth only sees the rocket in motion and thus shortened (along with the twin) while the destination planet is at rest in the earth frame and the distance to it is not contracted. However, the rocket twin sees the destination planet approaching at high speed and thus the entire distance to the planet is contracted and covered in a shorter time. The Return Trip seems subject to identical considerations of shorter travel versus the Earth Twin..

It is true that the rocket twin will see time passing more slowly on the Earth Twin's clock and so they will arrive back with their version of the Earth Twin's clock consistent with their shorter trip and their earlier age.
 
  • Like
Likes FactChecker
Physics news on Phys.org
Totally have it now, many thanks - this can be closed now!
 
I guess you could make an explanation of the twin paradox based on length contraction. But I think most people who struggle with time dilation in this scenario will struggle even more with length contraction.
 
As with any misguiding paradox, one should address the misconception that leads to the paradox. IMO, they have no problem with SR time dilation or length contraction. In the Twins Paradox, the basic misconception is the belief that the situation of the two twins is symmetrical and identical. The OP shoots holes in that belief in a simple way. I think it is a good point.
 
MOVING CLOCKS In this section, we show that clocks moving at high speeds run slowly. We construct a clock, called a light clock, using a stick of proper lenght ##L_0##, and two mirrors. The two mirrors face each other, and a pulse of light bounces back and forth betweem them. Each time the light pulse strikes one of the mirrors, say the lower mirror, the clock is said to tick. Between successive ticks the light pulse travels a distance ##2L_0## in the proper reference of frame of the clock...

Similar threads

  • · Replies 35 ·
2
Replies
35
Views
3K
  • · Replies 43 ·
2
Replies
43
Views
4K
  • · Replies 4 ·
Replies
4
Views
1K
  • · Replies 20 ·
Replies
20
Views
3K
  • · Replies 137 ·
5
Replies
137
Views
10K
  • · Replies 31 ·
2
Replies
31
Views
3K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 70 ·
3
Replies
70
Views
7K
  • · Replies 11 ·
Replies
11
Views
2K
  • · Replies 10 ·
Replies
10
Views
3K